Is there any way to duplicate bones radially?
Just an idea... you can dupliface the armature:



Here I used a cylinder: the number of faces will make the radial distribution.

Once original armature is ok, you need:


to select the cylinder and make duplicate real
to select the duplicated armature and make them single user
then join them:




Though, I don't think there is a mean to duplicate the eventually created animation on the original armature by this way...